1. The Field of the Invention
This invention relates to anchors that can be disassembled into modular components and stored and transported in a kit. More specifically, this invention relates to a modular anchor with an articulated arm that can pivot when the stress to which a releasing mechanism is subjected surpasses a critical break point.
2. Relevant Technology
An anchor is any device used to secure a floating body to the bottom of a body of water. An anchor cable is any line, wire, chain, etc., that runs from the floating body to the anchor. It is called an anchor cable, regardless of its configuration. The term "boat" will hereinafter refer to any floating body that is made fast by means of an anchor.
The parts of an anchor comprise a shank, arms terminating in flukes, a crown, and a stock. Although these parts are designated by well-known terms in the art, these parts are briefly characterized below for introducing basic terminology.
The shank is an elongated body with two ends. One of the shank's ends has an orifice or similar feature for attachment of the anchor cable, either directly or by means for linking an anchor cable with the shank end, such as a ring or a ring and a shackle. An anchor buoy may also be connected by a taut line to an anchor at this orifice. At its other end, the shank forms the crown. In some anchors, two arms attach to the shank at the crown.
The arms extend away from the crown and terminate in flukes, which are pointed structures for digging into the floor at the bottom of a body of water. The floor at the bottom of a body of water is hereinafter referred to as "floor". When the flukes dig into the floor and the anchor holds the ground well, it is said to bite. When the anchor bites, the fluke or flukes and the shank define an angle that is typically less than 90.degree..
Some anchors do not have arms, and the flukes are attached directly or very close to the crown or to the corresponding end of the shank. Typically, anchors with arms have a generally longitudinal stock at the end of the shank opposite to the crown. The stock is usually perpendicular to the shank and it is contained in a plane that is perpendicular to the plane that contains the arms. In some anchors with no arms, the stock extends away form the crown, in about equal lengths to each side, and the flukes, usually twin flukes, are mounted one on each side of the crown. Other anchors have no stock. See A. Ansted, A Dictionary of Sea Terms, pages 3-4, (1985)(this book will hereinafter be referred to as "Dictionary of Sea Terms").
Anchors receive different names depending on their parts. For example, the Admiralty Pattern or Fisherman's Anchor has a stock at right angles to the arms which causes the anchor to lie so that one of the flukes will bite into the floor. It has been in use for about 2000 years, but it has been superseded for a number of applications by the Stockless Anchor. The arms of the Stockless Anchor hinge on the shank and usually have tripping palms which cause the flukes to bite into the ground when a pull is exerted on the anchor. The Danforth Anchor has a light stock at the crown extending beyond the flukes to ensure that both flukes lie flat and bite into the ground. The Plough, Ploughshare or CQR Anchor ("CQR" merely being a phonetic play on "secure") is nowadays usually carried by small boats. It is also used to anchor floating objects such as buoys and platforms. In this stockless anchor, the flukes, shaped like ploughshares, turn on the shank and dig into the ground when the boat pulls upon its anchor. Stockless anchors are generally referred to with the terms "patent anchors". The Mushroom Anchor is shaped as its name indicates and it is usually employed on mud or other soft floors. See Dictionary of Sea Terms, pages 4-5; C. W. T. Layton, Dictionary of Nautical Words and Terms, page 14 (1982); John V. Noel, Jr., and Edward L. Beach, Naval Terms Dictionary, page 208 (1988);Graham Blackburn, The Illustrated Dictionary of Nautical Terms, pages 92, 101 (1981); Jane's Dictionary of Naval Terms, compiled by Joseph Palmer, page 8 (1975), and for illustrations of different types of anchors, see Thompson Lenfestey, Dictionary of Nautical Terms, page 14 (1994). A solid anchor is one where the shank and flukes are forged together, while a portable anchor, hereinafter referred to as a "modular anchor" is capable of being taken to pieces. See Gershom Bradford, The Mariner's Dictionary, page 7 (1972) (this book will hereinafter be referred to as "Mariner's Dictionary"). Modem anchors of light weight and high tensile strength are popular for boats of small tonnage, especially yachts. See Mariner's Dictionary, page 8.
Pulling from an anchor's shank usually digs the fluke's tip into the floor, thus making the anchor bite. The anchor's bite prevents the boat from drifting away from a determined area in which the boat is to remain. When the boat is to be under way again, its anchor has to be retrieved from the floor. To weigh anchor is to get the anchor up in preparation for getting under way. This is done by first heaving short, which is performed by hauling upon the anchor cable until the boat is nearly over its anchor, a maneuver that should ordinarily bring the anchor apeak. This is the anchor's position when it stands on its crown. The anchor is subsequently lifted form the floor, at which point the anchor is aweigh, and ultimately awash or above the water surface. The boat has been under weigh from the moment its anchor is weighed. See Dictionary of Sea Terms, pages 3-4.
This entire maneuver of getting the boat under weigh can be accomplished provided that the anchor bites the floor without sticking the flukes under a heavy object that will prevent the fluke tips from generally pointing upwards. In other words, when the flukes get stuck or entangled, the anchor will not be apeak at the end of the process of heaving short and the anchor's retrieval will be difficult or impossible. Although reportedly infrequently, the impossibility of getting the anchor aweigh and its subsequent loss is reflected by the incorporation in insurance policies of an Anchor and Chain Clause. According to this marine insurance clause, the underwriter is typically free from expenses to recover lost anchors and chains lost while the boat is afloat. See Eric Sullivan, The Marine Encyclopaedic Dictionary, 5th ed., page 23, (1996), and John V. Noel, The VNR Dictionary of Ships & The Sea, page 9 (1981). These references referred to hereinabove are hereby incorporated by reference.
A number of patents have disclosed anchors of different types. Generally, most anchors' designs focus on the improvement of features that will enhance the anchor's holding ability. These features include flukes that can pivot over a limited angular range. Limited pivoting is usually accomplished by structural elements whose function is to prevent the flukes from widely pivoting. In other words, these structural elements actually confine the angle defined by the shank and the flukes to an angle that is significantly less than 90.degree.. These include U.S. Pat. No. 5,154,133 to Hallerberg which discloses a twin-fluke anchor that can be assembled in two different configurations to vary the shank-fluke angle to optimize the anchor's holding power. The assembly allows for limited pivoting of the shank relative to the twin flukes. U.S. Pat. No. 4,058,078 to Stelling discloses a twin-fluke anchor in which the flukes are mounted on a cross-bar that is orthogonal to the anchor's shank. The shank is allowed limited pivoting about the cross-bar. U.S. Pat. No. 3,766,877 to Beck discloses a pivoted fluke anchor with shank, fluke, and stock that have surfaces that are substantially free of obstructions to the flow of bottom soil thereover. U.S. Pat. No. 3,759,212 to Cluett discloses an anchor comprising preferably a single, replaceable fluke, and a hinged shank. The hinged shank comprises two sections each secured to an opposite end of an elastically extensible shock cord. In this anchor, the shank is structured to reduce shock transmitted from a fixed anchorage to the anchor, rode, and deck mooring gear. Preferably, this anchor includes a single, replaceable fluke which is pinned at an angle to the shank during use, and which can be folded for storage. U.S. Pat. No. 3,306,248 to Austin discloses a twin-fluke anchor with a floating device to orient the tips of the flukes and a pin-based mechanism to adjust the maximum pivoting angle of the shank with respect to the anchor's stock. This angle can be adjusted for different earth conditions on the bottom of the river, lake or sea in which the boat is to be anchored.
Although considerable attention has been given to the improvement of the anchor's design for enhancing the anchor's bite to a variety of floor conditions, a considerable smaller number of references address the problem of retrieving an anchor that is stuck or wedged on the floor. This problem is addressed in U.S. Pat. No. 2,948,249 to Gesner et al. which discloses a collapsible single-fluke and shank anchor with a means for facilitating the anchor's release when it is engaged with the bottom of a body of water. To facilitate its release, the anchor's shank engages the fluke by means of a resilient holding clamp and a pivoting attachment with a cross-arm. This pivoting attachment permits the shank to pivot almost freely when it is dislodged from the holding clamp, thus facilitating the retrieval of the entire anchor.
The engagement of an anchor's shank with a resilient holding clamp in the fluke is a release mechanism whose actuation will be increasingly less predictable and reproducible as the number of actuations increases. By repeatedly removing the shank from the holding clamp and reinserting it into the holding clamp, the clamp's resilience will diminish and it will also wear out by friction. Consequently, the holding ability of the shank and holding clamp assembly will gradually become less predictable and reproducible. In addition, rust removal and general maintenance operations is most likely to lead to additional wear of the holding clamp and shank system. Whereas replacement of worn out or non-conforming parts is a solution that often restores standard working conditions to an otherwise poorly performing mechanism, replacement is difficult when the holding clamp is built into the fluke, for its replacement would imply the disposal of the anchor or at least of its fluke, or the involvement of significant specialized work for removing and reattaching the worn out parts.
Conventional anchors do not have simple, reproducible and predictable features that would allow for the easy retrieval of the anchor when it is stuck in the floor. Recovery of these anchors becomes difficult or impossible. It is therefore desirable to provide an anchor with built in features that are simple, whose behavior is reproducible and predictable, and that facilitate the easy retrieval of the anchor when it would otherwise have to be abandoned on the floor after considerable time spent in attempting to free and recover it.
Each one of the afore-mentioned patents is hereby incorporated by reference in its entirety for the material disclosed therein.